JPH05340690A - Cooling tower and cooling capacity control method - Google Patents

Abstract

PURPOSE:To provide a cooling tower which performs operation responding to a cooling water temperature. CONSTITUTION:In a cooling tower 10, a fan motor 13 is arranged to the inner upper part of a casing 11, a fan 14 is run with the aid of the fan motor 13, cooling water is cooled by dripping cooling water from a sprinkler 15 in the casing 11 to a filler unit 16, and cooling water after cooling can be stored in a water tank 12. The temperature of cooling water fed to a freezer 20 is detected by a cooling water temperature sensor 51, and fed to a control device 53 of an operation control device 50. In a control device 53, during the starting of the fan motor 13, a frequency signal changed at intervals of a given time is outputted until a frequency attains a set value determined by a cooling water temperature detected by the cooling water temperature sensor 51. A frequency signal from the control device 53 is fed to an inverter device 55. The inverter device 55 rotationally drives the fan motor 13 according to the frequency signal therefrom. This constitution and method regulate an airflow of the cooling tower 10 and regulate cooling capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling tower capable of controlling the fan motor of the cooling tower to operate in accordance with the cooling water temperature, and a cooling capacity control method thereof.

[0002]

2. Description of the Related Art A conventional cooling tower of this type is known as an apparatus for cooling cooling water which has become hot by contacting it with the atmosphere and mainly by latent heat of vaporization of the cooling water.

FIG. 6 is an explanatory view showing a partial cross-section of an example of a conventional refrigeration system using a cooling tower.

The refrigeration system shown in FIG. 6 has a cooling tower 110.
And the refrigerator 120 are connected by a cooling water pipe 130.

Here, the cooling tower 110 has a casing 111 having a shape as shown in the drawing, and is constructed as follows. The casing 111 has an opening H formed on the upper side of the drawing and a water tank 112 formed on the lower side of the drawing. An opening W is provided immediately above the water tank 112 in the circumferential direction of the casing 111. A fan motor 113 is fixed to the opening H of the casing 111 with a fixture M. A fan 114 is fixed to the rotation shaft of the fan motor 113. A water sprinkler 115 is provided below the fan 114 inside the casing 111. This sprinkler 115
A filler unit 116 is filled between the lower part of the above and the upper part of the opening W. A louver 117 is provided in the opening W. A cooling water temperature sensor 118 is arranged in the water tank 112, and the fan motor 11 is responsive to the temperature detected by the cooling water temperature sensor 118.
3 is on / off controlled. The makeup water for the cooling water is supplied from the water supply port.

The cooling water pipe 130 comprises a forward pipe 131 and a return pipe 132. Further, the forward pipe 131 is provided with a cooling water pump 133 and a check valve 134.

The operation of the cooling tower in such a refrigeration system will be described with reference to FIGS. 7 and 8.

FIG. 7 is an explanatory view showing the operation stop pattern of the fan motor of the conventional cooling tower, in which the horizontal axis represents the cooling water temperature [degrees C] and the vertical axis represents the frequency [Hz]. ..

FIG. 8 is a diagram for explaining a state in which the fan motor is repeatedly stopped depending on the cooling water temperature. The horizontal axis represents time [h] and the vertical axis represents the cooling water temperature. is there.

Thus, the fan 1 of the conventional cooling tower 110 is
As shown in FIG. 7, when the cooling water temperature detected by the cooling water temperature sensor 118 is, for example, 27 [degrees C] or higher, the fan motor 113 is turned on, and the cooling water temperature is, for example, 24.5. The operation is controlled so as to be turned off at a temperature of [degree C] or less.

Therefore, when the cooling water heated in the refrigerator 120 is sprayed from the sprinkler 115 of the cooling tower 110 to the filler unit 116, the air that is passed by the fan 114 while flowing down the filler unit 116. Contact with
It is cooled mainly by latent heat of vaporization and stored in the water tank 112. The cooling water stored in the water tank 112 is sucked by the cooling water pump 133 and supplied to the refrigerator 120 via the forward pipe 131. Thereby, the heat of condensation generated in the refrigerator 120 can be removed.

That is, as described above, the conventional cooling capacity control method for the cooling tower has been so-called on / off control in which the fan 114 is simply operated or stopped.

[0013]

In the conventional cooling tower described above, when the atmospheric temperature is low or the heat load of the refrigerator is small, the on / off set temperature of the fan motor (27 [degree C. ], The fan is frequently turned on and off during 24.5 [degrees C]).
In such an operating state, as shown in FIG. 8, the cooling water temperature fluctuates greatly, and stable operation cannot be performed, resulting in the following drawbacks.

(1) During the time when the load is light, the fan of the cooling tower is repeatedly operated and stopped frequently, and the life of the fan and the fan motor is significantly shortened.

(2) The operating noise during fan operation / stop is high.

(3) When the load is high and the wet-bulb temperature is 27 degrees C or higher, the cooling capacity becomes insufficient.

(4) The cooling water temperature changes abruptly, which adversely affects the refrigerator.

An object of the present invention is to provide a cooling tower and a cooling capacity control method for the cooling tower, which can solve the above-mentioned drawbacks and can be operated according to the cooling water temperature.

[0019]

In order to achieve the above-mentioned object, a cooling tower according to the present invention is provided with a fan motor in an upper part inside a casing, the fan is rotated by the rotation of the fan motor, and a water sprinkler inside the casing. Cooling water by dropping cooling water to the filler unit from, in a cooling tower that can store the cooling water after cooling in the lower water tank, a temperature sensor for detecting the temperature of the cooling water, and at the time of starting the fan motor, A control device that outputs a frequency signal that changes every predetermined time up to a frequency set value determined by the cooling water temperature from the temperature sensor, and an inverter device that rotationally drives the fan motor according to a signal from the control device are provided. It is characterized by that.

In order to achieve the above-mentioned object, the cooling capacity control method of the cooling tower according to the present invention is provided with a fan motor in the upper part inside the casing, the fan is rotated by the rotation of the fan motor, and the water is sprinkled inside the casing. In the cooling capacity control method of the cooling tower, which cools the cooling water by dropping the cooling water from the container to the filler unit, and can store the cooling water after cooling in the lower water tank, a fan is set according to the cooling water temperature of the cooling tower. It is characterized by controlling the air flow rate.

[0021]

Therefore, according to the cooling tower of the present invention, when the detected temperature of the cooling water from the cooling water temperature sensor is between the predetermined set temperatures, the controller outputs a frequency signal corresponding to the temperature. It will be. The inverter device controls the rotation of the fan motor by this frequency signal.

According to the cooling capacity control method of the cooling tower of the present invention, when the cooling water temperature is between the predetermined set temperatures, the rotation speed of the fan is varied according to the cooling water temperature to cool the cooling tower. The cooling capacity can be adjusted because the amount of airflow is changed.

[0023]

Embodiments of the present invention will be described below.

FIG. 1 is a diagram showing an embodiment of an operation control device for a cooling tower of the present invention.

The refrigeration system shown in FIG.
, Refrigerator 20, cooling water pipe 30, and bypass device 4
0 and the operation control device 50.

Here, the cooling tower 10 has a casing 11 having a shape as shown in the figure, and is constructed as follows. This casing 11 has an opening H on the upper side in the drawing.
And a water tank 12 is formed in the lower part of the drawing. An opening W is provided immediately above the water tank 12 in the circumferential direction of the casing 11. A fan motor 13 is fixed to the opening H of the casing 11 with a fixture M. A fan 14 is fixed to the rotation shaft of the fan motor 13. The casing 1
A water sprinkler 15 is provided in the lower part of the fan 14 inside 1. A filler unit 16 is filled between the lower part of the sprinkler 15 and the upper part of the opening W. A louver 17 is provided in the opening W. The replenishing water for the cooling water to the water tank 12 of the cooling tower 10 is supplied from a water supply port having a ball tap or the like (not shown).

The cooling water pipe 30 comprises a forward pipe 31 and a return pipe 32. A cooling water pump 33 and a check valve 34 are arranged in the outward pipe 31. A cooling water temperature sensor 51 is provided at the inlet of the refrigerator 20 of the outward pipe 31. The output signal of the cooling water temperature sensor 51 is used as the operation control device 50.
Has been entered in.

The bypass device 40 comprises an electric three-way valve 41 provided in the middle of the return pipe 32 and a pipe 42 for guiding the cooling water of the return pipe 32 to the water tank 12 when the three-way valve 41 is opened by a bypass command. It is configured.

The operation control device 50 comprises a control device 53 and an inverter device 55. The control device 53 forms a frequency signal that changes every predetermined time up to a frequency set value determined by the detected temperature signal from the cooling water temperature sensor 51, and supplies the frequency signal to the inverter device 55. In addition, the control device 53
Generates a bypass command signal based on the detected temperature signal from the cooling water temperature sensor 51 and supplies it to the bypass device 40.
The inverter device 55 controls the rotation speed of the fan motor 13 based on the frequency signal.

FIG. 2 is a block diagram showing a detailed configuration of the control device 53.

The control device 53 shown in FIG. 2 comprises a central processing unit 531, a storage device 532, an input signal section 533, and an output signal section 534, and is constructed as follows. When a switch (not shown) is turned on at the start of operation of the cooling tower, the control device 53 starts operation. Then, the central processing unit 531 operates based on the program stored in the storage device 532, and based on the data taken from the cooling water temperature sensor 51 via the input signal unit 533, the frequency determined by the detected temperature signal. The circuit configuration is such that a frequency signal that changes up to a set value at every predetermined time is formed and the formed frequency signal can be supplied to the inverter device 55 via the output signal unit 534. The frequency signal output from the output signal unit 534 is normally output with an output width of 0 to 5 [V] or 0 to 10 [V].

The operation of the embodiment thus configured is shown in FIG.
And based on FIG. 2, it demonstrates with reference to FIGS. First, the description of FIGS. 3 to 5 will be given.

FIG. 3 is an operating characteristic diagram showing an acceleration / deceleration pattern when the fan according to the embodiment of the present invention is operated / stopped.
In FIG. 3, the horizontal axis represents the operating time and the vertical axis represents the frequency [Hz], and the pattern for reducing torque is set in consideration of the applied load characteristics. Further, in FIG. 3, the conventional operation pattern is indicated by a broken line, and the operation pattern of the present invention is indicated by a solid line, so that the difference between the operation patterns can be easily understood.

FIG. 4 is a diagram for explaining an example of the structure of the frequency signal with respect to the cooling water temperature formed by the control device according to the embodiment of the present invention. Each frequency [Hz] is taken.

FIG. 5 is a characteristic diagram showing a cooling water temperature pattern during low cooling water operation, in which the horizontal axis represents the operating time [h] and the vertical axis represents the cooling water temperature [degree C]. Also,
In FIG. 5, the conventional operation pattern is indicated by a broken line and the operation pattern of the present invention is indicated by a solid line to facilitate understanding of the features of the present invention.

<Operation at the time of starting and ending of operation> Here, the operation at the time of starting of this embodiment will be described. When the refrigeration system starts, the operation control device 50 also operates. Then, as shown in FIG. 3, the control device 53 of the operation control device 50 operates in the set acceleration time Ta from the start of the fan motor 13 until the base frequency (normally 50 [Hz] or 60 [Hz]) is reached. A frequency signal that is changed in a pattern in which the frequency increases every time (second) is formed and input to the inverter device 55. As a result, the fan 14 is operated such that the rotation thereof gradually increases. On the other hand, in the cooling tower to which the present invention is not applied, the fan motor 10
It will be started within [seconds], noise will be generated, and the life of the fan / fan motor will be shortened due to the influence of inertia.

Next, the operation at the end of the operation of this embodiment will be described. When the refrigeration system is stopped, as shown in FIG. 3, from the base frequency (usually 50 [Hz] or 60 [Hz]) to the stop. At the set deceleration time Tb, a frequency signal is generated which is changed in a pattern in which the frequency decreases every operating time (second), and is input to the inverter device 55. As a result, the fan 14 operates in such a manner that the rotation thereof gradually decreases.

The control device 53 can arbitrarily set a straight line (for constant torque) or an S-shaped pattern in the acceleration / deceleration pattern shown in FIG. As a result, the load at the time of starting can be reduced and the life of the fan 14 and the fan motor 13 can be extended. Also, the operating noise at the time of startup is reduced by setting the acceleration / deceleration time.

<Operation Control Based on Cooling Water Temperature> Here, the operation control of the fan motor 13 based on the cooling water temperature will be described.

The temperature of the cooling water supplied from the cooling tower 10 to the refrigerator 20 is detected by the cooling water temperature sensor 51. The detected temperature signal detected by the cooling water temperature sensor 51 is given to the central processing unit 531 via the input signal unit 532 of the control device 53. As a result, the central processing unit 531 executes the following processing according to the program in the storage device 532. That is, the cooling water temperature sensor 5
If the temperature detection signal from 1 is equal to or lower than the set temperature of 24.5 [degree C], the central processing unit 531 does not output the frequency signal. When the temperature detection signal from the cooling water temperature sensor 51 exceeds the set temperature 24.5 [C] and is equal to or lower than the set temperature 27 [C], the central processing unit 531
As shown in FIG. 4, a frequency signal corresponding to the detected temperature is formed between the set temperatures, and the frequency signal is given to the inverter device 55 via the output signal unit 524. Thereby, the inverter device 55 rotationally drives the fan motor 13 at the frequency. In this way, the rotation speed of the fan 14 is controlled according to the cooling water temperature and the cooling capacity of the cooling tower 10 is adjusted, so that the cooling water at the optimum temperature for the capacity of the refrigerator 20 can be supplied to the refrigerator 20. ..

Therefore, conventionally, for example, the set temperature 24.
When the temperature exceeds 5 [degrees C] and the set temperature is 27 [degrees C] or less, the fan motor 13 is repeatedly turned on and off, and the cooling water temperature fluctuates as shown by the broken line K in FIG. According to this embodiment, the cooling water temperature changes smoothly as indicated by the solid line L in FIG.

As described above, in this embodiment, the rotation speed of the fan motor 13 is controlled by the control device 53 and the inverter device 55 in accordance with the temperature detection signal from the cooling water temperature sensor 51.

In the case of the conventional cooling tower, when the wet-bulb temperature at the air inlet is, for example, 27 [degrees C] and the load factor is high, the outlet temperature of the cooling water at the cooling tower rises above the design value (cooling). Lack of capacity).

Even in such a case, in the present invention, if the cooling water outlet temperature becomes, for example, 32 [degree C] (design value) or more, the control device 53 causes the base frequency (in this example, 60 [H]
z]) By forming the frequency signal as described above, the rotation speed of the fan motor 13 can be increased, the capacity can be improved, and the cooling water temperature can be lowered.

In the embodiment shown in FIG. 1, the three-way valve 4
The bypass device 40 composed of 1 and the pipe 42 is incorporated so that when the cooling water temperature is, for example, 24 [degrees C] or lower, the three-way valve 41 is switched by the output signal from the control device 53 of the operation control device 50, and the refrigeration The return cooling water from the machine 20 is dropped directly into the water tank 12 of the cooling tower 10 to prevent the cooling water and thus the refrigerator 20 from being overcooled.

[0046]

As described above, according to the cooling tower of the present invention, the rotation of the fan motor can be controlled according to the temperature of the cooling water, so that the following effects can be obtained.

(1) It is possible to significantly reduce the operation and stoppage of the fan and fan motor during the nighttime operation and the low load operation during the intermediate period when the cooling tower is operated for a long time.

(2) Reducing the number of operations / stops significantly extends the service life of operating parts such as fans and fan motors.

(3) Driving noise can be reduced by rotationally driving the fan motor according to the set acceleration / deceleration pattern at the time of starting and stopping.

(4) Even if the wet-bulb temperature at the air inlet of the cooling tower is above a certain temperature, the air volume can be increased and the cooling capacity is improved.

(5) Even in the operation of low cooling water, it is possible to maintain an operating state in which there is no significant fluctuation in the refrigerator.

Further, according to the cooling capacity control method of the cooling tower of the second aspect of the present invention, since the air volume of the cooling tower is changed according to the cooling water temperature, the cooling water of the optimum temperature can be always supplied.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration system to which an embodiment of a cooling tower of the present invention is applied.

FIG. 2 is a block diagram showing a configuration example of a control device used in an embodiment of the present invention.

FIG. 3 is a characteristic diagram showing an operation pattern of an example of the present invention together with a conventional operation pattern.

FIG. 4 is an explanatory diagram showing frequencies during operation of the fan motor with respect to cooling water according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a cooling water temperature change according to an operation pattern of an embodiment of the present invention together with a cooling water temperature change according to a conventional operation pattern.

FIG. 6 is a configuration diagram showing a refrigeration system including a conventional cooling tower.

FIG. 7 is a diagram showing an operation pattern of a conventional cooling tower.

FIG. 8 is an explanatory diagram showing a change in cooling water temperature according to an operation pattern of a conventional cooling tower.

[Explanation of symbols]

 10 Cooling Tower 11 Casing 12 Water Tank 13 Fan Motor 14 Fan 16 Filler Unit 20 Refrigerator 30 Cooling Water Pipe 31 Outgoing Pipe 32 Return Pipe 33 Cooling Water Pump 34 Check Valve 40 Bypass Device 41 Three-way Valve 42 Piping 50 Operation Control Device 51 Cooling water temperature sensor 53 Control device 55 Inverter device

Claims (2)

[Claims] 1. A fan motor is provided in the upper part of the casing, the fan is rotated by the rotation of the fan motor, and the cooling water is dropped from a sprinkler inside the casing to a filler unit to cool the cooling water, and then the lower water tank is provided. In a cooling tower that can store cooling water after cooling, a temperature sensor that detects the temperature of the cooling water and, at the time of starting the fan motor, change to a frequency set value determined by the cooling water temperature from the temperature sensor every predetermined time. A cooling tower comprising: a control device that outputs a frequency signal; and an inverter device that rotationally drives the fan motor according to a signal from the control device. 2. A fan motor is provided in the upper part of the casing, the fan is rotated by the rotation of the fan motor, and cooling water is dripped from a sprinkler inside the casing to a filler unit to cool the cooling water, and the lower water tank is provided. A cooling capacity control method for a cooling tower, which is capable of storing cooling water after cooling, characterized in that the amount of air blown by a fan is controlled according to the cooling water temperature of the cooling tower.